Approximate Analysis of Load Dstribution in Three-Dimensional Tall Building Structures

An approximate method is presented for the analysis of the distribution of lateral forces among the components of a three-dimensional tall building structure that consists of assemblies of shear walls, coupled walls, rigidly-jointed frames and cores, subjected to both bending and torsion. The load distribution on each element is assumed to be represented sufficiently accurately by a concentrated interactive force at the top together with a polynomial in the height coordinate. A set of flexibility influence coefficients, relating the deflection at any level to any particular load component, is established for each element, the continuum approach being used to analyse individual cores and coupled shear walls, and the shear cantilever analogy for the frame elements. By making use of the equilibrium and compatibility equations at any desired set of reference levels, the load distribution on each assembly may be determined. The accuracy of the technique, and the number of reference levels, were examined by comparing the results with those obtained from an 'exact' solution and those from two example structures which were analysed previously by various investigators. Finally, a parameter study has been carried out also to study the effect on the number of reference levels used